diff --git a/src/DataObject/Data/Adapter/LocalizedFieldsAdapter.php b/src/DataObject/Data/Adapter/LocalizedFieldsAdapter.php
index ea6d1bf7a..2e5935a49 100644
--- a/src/DataObject/Data/Adapter/LocalizedFieldsAdapter.php
+++ b/src/DataObject/Data/Adapter/LocalizedFieldsAdapter.php
@@ -136,7 +136,7 @@ public function normalize(
             ElementPermissions::LANGUAGE_VIEW_PERMISSIONS
         );
 
-        $attributes = array_keys(reset($originalValue));
+        $attributes = array_keys(array_merge(...array_values($originalValue)));
         $result = [];
         foreach ($attributes as $attribute) {
             foreach ($languages as $language) {